H. Russ et al., AGE OF THE UNIVERSE - INFLUENCE OF THE INHOMOGENEITIES ON THE GLOBAL EXPANSION FACTOR, Physical review. D. Particles and fields, 56(4), 1997, pp. 2044-2050
For the first time wt calculate quantitatively the influence of inhomo
geneities on the global expansion factor by averaging the Friedmann eq
uation, In the framework of the relativistic second-order Zel'dovich-a
pproximation scheme for irrotational dust we use observational results
in the form of the normalization constant fixed by the Cosmic Backgro
und Explorer results and ive check different pou er spectra, namely, f
or adiabatic cold dark matter (CDM), isocurvature CDM, hot dark matter
, warm dark matter, strings, and textures, We find that the influence
of the inhomogeneities on the global expansion factor is very small. S
o the error in determining the age of the universe using the Hubble co
nstant in the usual way is negligible. This does not imply that the ef
fect is negligible far local astronomical measurements of the Hubble c
onstant. Locally the determination of the redshift-distance relation c
an be strongly influenced by the peculiar velocity fields due to inhom
ogeneities. Our calculation does not consider such effects, but is con
strained to comparing globally homogeneous and averaged inhomogeneous
matter distributions, In addition we relate our work to previous treat
ments.